Outlet winker



United States Patent OUTLET WINKER Louis Ludwig, New York, N.Y.

Application November 8, 1956, Serial No. 621,145

6 Claims. (Cl. 200--115.5)

This invention relates to an outlet winker, a term conventionally employed to denote an electric device which includes a pair of male prong contacts and a pair of female contacts, between one associated set of which there is located an electrically actuable intermittent circuit interrupter whereby the winker can be plugged into an outlet and can have plugged into it the conventional bayonet plug of an electric lighting fixture as, for instance a Christmas tree string, which thereby is rendered intermittently operable so as to provide a desired flashing, i.e., winking, effect.

Considerable difficulty has been experienced for many years in the fabrication of outlet winkers of the character described due to the fact that it has not proven feasible, despite the use of standardized parts, to provide a flashing time of any specified interval which would be reasonably consistent for all of a production run of winkers.

The winker employed for the intermittent flashing effect comprises a thermoblade carrying a contact. Said contact is designed to move so as to intermittently engage a stationary contact through which line current thereupon flows. When the contacts are spaced apart, the line current energizes a heating coil for the blade, said coil being shunted during the contact engagement, so that the heating likewise is intermittent. The movement of the thermoblade under these conditions is comparatively slight so that the mounting of the blade greatly influences the winking interval. However, it has not been possible, taking into account the factors attendant upon mass production, heretofore to uniformly mount the thermoblades. Invariably, all means utilized to secure the thermoblades in position have permitted some play or deviation of the blades which made the winking period inconstant as between winkers in the same manufacturing run and, indeed, very often in the same blade operated under different conditions. For instance, sometimes even a slight transverse pressure on the male prongs of an outlet winker would drastically affect the flashing time. Often the position of the thermoblade would be so seriously deranged by purely fortuitous circumstances that either the winker would not flash at all, i.e., give a steady light, or would hold the circuit permanently open with resulting inoperativeness of the electric light fixture connected thereto.

It is an object of my invention to provide a winker of the character described which will uniformly provide substantially consistent flashing despite the circumstances in which it finds itself employed and which can be relied upon always to intermittently energize an electric fixture attached thereto.

It is another object of my invention to provide a winker of the character described the construction whereof, although particularly rugged and durable, is unusually simple and can, therefore, be made by simple mechanical mass-operated steps.

Another object of my invention is to provide a winker of the character described in which the interior portion of the male contact prong to which the thermoblade is secured is rigidly aflixed in a novel manner to the winker casing.

Other objects of my invention in part will be obvious and in part will be pointed out hereinafter.

My invention accordingly consists in the features of construction, combinations of elements and arrangements of parts, which will be exemplified in the device hereinafter described and of which the scope of application Will be indicated in the appended claims.

In the accompanying drawings, in which are shown various possible embodiments 'of my invention,

Fig. 1 is a front view of a winker constructed in accordance with my present invention;

Fig. 2 is an enlarged front view of the winker with the internal parts thereof exposed by removal of one of the casing halves;

Fig. 3 is an enlarged view of that portion of the exposed internal winker construction which provides a particularly secure mounting for the male contact prong to which the thermoblade is rigidly affixed;

Fig. 4 is an enlarged fragmentary sectional view taken substantially along the line 4-4 of Fig. 3;

Fig. 5 is an enlarged fragmentary detail view showing the shank of the male prong and the associated part of the casing half as they appear prior to assembly;

Fig. 6 is a view similar to Fig. 5 but illustrating said prong and casing half during assembly thereof;

Fig. 7 is another view similar to Fig. 5 but showing said prong and easing half after final assembly;

Fig. 8 is a view similar to Fig. 3 on a slightly reduced scale of a winker embodying a modified form of my invention;

Fig. 9 is an enlarged sectional view taken substantially along the line 9-9 of Fig. 8; and

Fig. 10 is a perspective view of a clip employed in said modified winker.

Referring now in detail to the drawings, and more particularly to Figs. 1*7, the reference numeral 10 denotes a winker constructed in accordance with the present invention. Said winker includes a casing 12 consisting of two halves 14, 16, made of an electrically non-conductive material, preferably a thermosetting synthetic resin such, for instance, as a phenol-formaldehyde condensation resin, so as to be unaffected by high temperatures. The two halves are formed, as by molding, to include suitable interior recesses, hereinafter described in more detail, for holding the internal parts of the winker, and with a suitable exterior surface the configuration of which provides a pleasing appearance. The interior configuration of the casing half 14 is conventional, as will appear hereinafter, my invention being concerned in part, however, with the interior configuration of the casing half 16.

The electrical components of the winker consist of a pair of male contacts and a pair of female contacts. More specifically, I include two male contact prongs 13, 20. Each of these prongs has a straight contact-engaging blade 22 of the usual shape and dimensions which is adapted to be coupled with a standard female contact. Each prong furthermore includes in one piece therewith an internally located shank 24 at the inner end of the blade and directed outwardly perpendicular thereto.

Reference first will be had to the prong 18, the construction whereof is conventional. The shank of said prong is provided with a through aperture 26 through which an eyelet 28 extends. Said eyelet further extends through an aperture (not shown) in the shank 30 of a female contact 32. The female contact and prong 18 are fabricated from electrically conductive material. However, the male contact 18 must be stiff, whereas the female contact is resilient. To this end, as is usual, the male contact is formed from comparatively thick stock which is relatively stiff, for example, thick brass stock. On the other hand, the female contact 32 is fashioned from comparatively thin springy stock as, for instance, Phosphor bronze, which is inherently of greater resilience than the brass stock.

Extending in a direction away from the male prong 18 the female contact 32 includes an arm 34 which is approximately parallel to and colinear with its afilliated male blade. A finger 36 extends outwardly away from the tip of the arm 34 at an angle thereto. The eyelet 28 firmly secures the female contact 32 to the male prong 18. As mentioned above, the construction of the male and female contacts 18, 32, respectively and their joinder, as by the eyelet 28, is standard, the same having been described in detail only for the purpose of completeness.

The winker casing half 16 includes several recesses receiving the male prong 18 and female contact 32 for the proper positioning thereof. Thus, said half 16 includes a transversely extending slot 38 in which the shanks 24, 30 are located. The head of the eyelet 28 protruding from the shank 30 of the female contact bears against a long wall 40 of said slot. The slot is provided with an outward reduced extension 42 for the snug reception of a finger 43 at the outer end of the prong shank 24, whereby to prevent axial movement (referring to the length of the blade 22) of said end of the prong. A protruding nub 44 extends into the slot 38 to bear against the surface of the prong shank remote from the female contact. It thus will be apparent that spaced points on the two shanks 24, 30, or parts in one piece therewith, bear against both long walls of the slot 38 and its extension 42 to hold the prong and contact against axial movement.

Transverse movement of the prong 18 is inhibited by the provision of a groove 46 connecting the slot 38 to the exterior of the casing half 16 adjacent the point of emergence of the blade 22. A portion of the blade 22 is snugly received in said groove.

The female contact 32, and particularly the arm 34 and finger 36, are located in an elongated cavity 48 which constitutes a widened extension of the groove 46 and is sufficiently large to permit free sidewise movement of said contact. The cavity 48 extends through the wall of the casing half 16 opposite to that from which the blade 22 projects, thus forming an opening and passageway for reception of the blade contact of an electrical lighting fixture, as, for example, a Christmas tree string.

The central section of the casing half 16 and the side section thereof at which the prong 18 and female contact 32 are located further include several recesses which have no functional purpose in connection with the interior components of the winker but are provided to lighten the casing without weakening the same to a point where it is no longer useful for its intended purpose to support and protect the male and female contacts. In addition, the casing half 16 is fashioned with a central well 50 to receive a suitable connecting means such, for instance, as a drive screw 52 that extends through a registered through opening (not shown) in the casing half 14 in order to hold the two halves together.

Referring now to the male prong 20, the shank 24 thereof is provided with suitable means to rigidly a'lfix thereto a thermoblade 54. Said means, as shown, constitutes a non-circular finger 56 which protrudes from and is in one piece with the outer end of said shank consisting, for instance, of a tit of rectangular cross-section, the thickness of which is the same as and coextensive with the thickness of the shank and the width of which is less than the width of the shank. The finger preferably is located centrally of the width of the shank thereby providing a step 58 on the shank to either side of the finger. The thermoblade is slightly narrower than the shank and is formed with a rectangular through opening adjacent its base which is of such configuration and dimensions that it can be snugly slipped over the finger 56 to abut against the shoulders at the end of the shank with the finger protruding from the opposite surface thereof.

In the assembly of the winker, after the thermoblade has been thus positioned, the finger 56 is peened to swell the cross-sectional area thereof where it extends through the opening in the thermoblade and to form a head on the finger on the outer surface of said blade thus rigidly and very firmly integrating the thermoblade with the prong 20. During this peening operation, the thermoblade and shank 24 of the prong 20 are held in jigs to maintain them in a certain, e.g., perpendicular, angular relationship which they will maintain permanently after the peening and which will position the thermoblade in a desired location within the casing, taking into account the mounting for the prong hereinafter described in detail.

The thermoblade conventionally constitutes a straight bimetallic strip, a portion whereof adjacent the shank of the prong 20 is ensheathed by a heat and electrical insulating tube 60 composed, for example, of a few convolutions of thin asbestos sheeting. An electrical resistance coil 62 is wrapped around the tube and one end thereof is electrically and physically connected to the shank of the prong 24, as by welding.

The free end of the thermoblade permanently carries a movable contact button, i.e., a button movable with said blade.

A female contact 66 is associated with the male prong 20. Said female contact comprises a base 68 which is secured to the casing half 16 as by a drive screw 70. Upstanding from the base is a flange 72 from which there extends an arm 74 carrying an outwardly inclined finger 76 at its tip. Said contact further includes an angle bracket 78 having a base overlying the base 68 and held against the same by the drive screw which passes through openings in both bases and is anchored in the material of the casing half 16. The angle bracket has an upstanding flange 80 on which there is permanently secured a stationary contact button 82. The two contact buttons normally, that is to say, when idle, are spaced apart as shown in Fig. 2, this spacing being determinative of the flashing period and of the operativeness of the winker. The other end of the coil 62 is connected, as by welding, to the angle bracket.

The operation of the winker is conventional in that when the male prong 20 and female contact 66 are series connected in an electric circuit, the current initially flowing therethrough will pass through the coil 62 where it generates heat that slowly permeates through the asbestos tube 60 to the thermoblade 54. The thermoblade is so constructed that raising the temperature thereof will cause the same to flex inwardly whereby after a predetermined interval of a few seconds after the winker first is energized, the button 64 will touch the button 82 allowing the full line current to flow to the device plugged into the winker. Such action will shunt the coil 62 and allow it to cool off so that shortly thereafter the buttons will move apart to interrupt energization of the device plugged into the winker and commence to regenerate heat in the coil 62. This cycle will repeat at regular periods.

It will be appreciated that precise operation of the winker is a function of the idle spacing between the two buttons and that this in turn depends upon the precise location of the shank 24 of the prong 20.

Accordingly, pursuant to my invention I provide a means for securely and solidly mounting said shank in the casing half 16 which means does not require the utilization of any manually manipulatable parts such, for instance, as screws, and which is assemblable by press operation so as to secure a firm set. Said means constitutes cooperating parts on the prong and the casing half. The prong part consists of the shank 24 which already has been 7 V described. The casing part consists in the configuration of recesses provided for this purpose. As shown in Figs. 1-7, said configuration is such as to clamp the shank as a beam in fiexure, i.e., to depress a central portion of the shank while firmly supporting the ends thereof. Moreover, the configuration is so arranged that the casing half frictionally engages the shank with a pressure greater than that which can be secured by a simple press fit between metal and plastic.

Specifically, I provide a transversely extending slot 84 in which the shank 24 of the prong is located. Said slot is fashioned with a pair of bosses 86, 88, of V-shaped cross-section, one located near the blade 22 and the other at a point remote therefrom and near the bimetallic strip 54. Both said bosses are disposed on the same side of the slot, this side, as shown, being that which is closest to the external surface of the casing half 16 from which the blades extend. On the other side of the slot 84 there is formed another boss 90 of round cross-section which is located between, preferably midway between, the bosses 86, 88. The perpendicular distance from the tip of the boss 90 to an imaginary line drawn between the tips of the two bosses 86, 88 is slightly less, e.g., 0.002 inch, than the thickness of the shank 24.

In Fig. 5 where I have shown the shank 24 as it appears prior to assembly in the casing half 16 I have somewhat exaggerated, for the purpose of illustration, the thickness of said shank with respect to the aforesaid perpendicular distance a between the boss 90 and the bosses 86, 88. In assembly of the prong and casing half 16, the shank is forced, long edge first, into the slot 84. The outer ends of the three bosses, i.e., the ends on the internal face of the casing half, are rounded or chamfered as indicated at 92 to facilitate entry of the shank into the slot. After the shank has passed these initially engaged rounded surfaces, the sharp leading corners of the shank will shave curls 94 (see Fig. 6) of the plastic from the tips of the bosses. At the same time, due to the lack of adequate width in said slot for merely snug reception of the shank and since the boss 90 lies between the two bosses 86, 88, said boss 90 will depress the central part of the shank located between the bosses 86, 88, thereby slightly flexing the shank which acts as a beam supported on the underlying bosses 86, 88 so that when theshank is finally seated against the bottom of the slot as shown in Fig. 7, the central portion of the shank will be slightly depressed (see Fig. 3). The flexion thus imparted to the shank creates a stress which is below the elastic limit for the material employed, so that with the shank in place there will be a residual substantial stress, the tendency of which is to straighten out the shank and thereby create a compressive stress at the zones of contact between the bosses and shank which is greater than the compressive stress which would result merely from a press fit of the shank into a slot.

In this fashion I have secured a particularly firm grip on the shank which will not be disturbed except by destroying the casing. This seating will hold the shank in place against all dislodging forces that may be applied accidentally during ordinary use and even will enable it to withstand severe abuse without in any wise disturbing the precise position the shank occupies in the winker casing. It will be appreciated that such construction also results in an exact location of the thermoblade which, as noted previously, is in immovable relationship to the shank. It thereby is possible even in large production runs to be sure that the movable contact button 64, is in the correct position desired with regard to the stationary contact button and all winkers thus made will operate in substantially the same fashion.

The casing half 16 further includes for snug reception of the blade 22 a groove 92 connecting the slot 84 to the exterior of the casing half 16 adjacent the point of emergence of said blade. In addition, the casing half is suitably recessed to permit free movement of the thermo- V 6 blade and reception of the fixed button support and female contact 66.

It should be pointed out that the casing half 16 receives only approximately one-half of the width of each of the two male prongs and female contacts, the remaining portions thereof extending above the interior surface of said casing half. These extending portions are received in the other casing half 14 which is suitably apertured to snugly receive the blades 22 and to freely receive the female contacts. The part of the casing half that receives the shank 24 of the prong 20 does not engage said shank in the same fashion as the casing half 16, said casing half 14 simply being designed to lightly rest against the shank 24 in its flexed position or, if desired, merely to provide room to accommodate the same without engaging it at all. It will be appreciated that no further engagement is necessary inasmuch as the casing half 16 and more particularly the bosses 86, 88, very firmly hold the shank 24 of the prong 20. After the two casing halves have been brought together with the electrical components located therein, the drive screw 52 is secured in place in the usual fashion so as to prevent the two halves from coming apart.

In the modified form of my invention shown in Figs. 23-10, the construction of the various parts of both the casing and electrical components of the winker is the same except for the particular means to hold the shank 24 of the prong 20' in place. Accordingly, the parts of the winker 100 which are the same as the parts of the winker 10 will be denoted by the same reference numerals primed.

The casing half 16 has a transversely extending slot 102 in which the shank 24' is located. Said slot is somewhat wider than the thickness of the stock forming the shank and receives therein a clip 104 of resilient metal which is of U-shaped transverse cross-section. The base 105 of the clip lies against the base of the slot 102, and the side walls 106, 108 of the clip lie against the side walls of the slot. The height of the clip does not exceed the height of the slot so that the clip does not extend above the inner surface of the casing half 16'. The breadth of the clip is substantially equal to the width of the slot so that the clip either is snugly or force-fitted into the slot, preferably force-fitted.

Desirably, the clip is inserted in the slot prior to mounting of the shank 24' therein. Tongues 110 are struck out from the side walls 106, 108 of the clip, being directed internally of the clip at a slight angle thereto so as to effectively reduce the internal width of the clip. It now will be apparent that when the shank is introduced into the clip, it must be forced into the same as in a press due to the tight fit. As the slot passes the tongues 110, said tongues will retract toward the side walls of the clip. After assembly is complete, the tongues will strongly press against the sides of the shank and, indeed, the free edges of the tongues will bite into the shank so as to make it impossible to withdraw the shank from the clip. Moreover, the pressure is so substantial that it is not possible in any way to shift the shank with respect to the clip. It is within the scope of my invention to omit the tongues 110 and force-fit the shank into the clip whereby the same rigid holding eifect is secured.

By virtue of the foregoing construction, I am able to secure a firm seating of the shank 24' in the casing half 16 so that the thermoblade 54' is securely and exactly held in place in order that its movable button will occupy a predetermined exact relationship with respect to the stationary button and all winkers of the same run will provide a substantially consistent flashing interval.

It thus will be seen that I have provided outlet winkers and method of making same which achieve the various objects of my invention and are well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a winker including a casing, a male contact prong having a shank of oblong cross-section and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely aflixing the thermoblade to the shank in exact angular relationship and position with respect thereto, bosses in one piece with the casing and extending from said walls into the groove, said bosses tightly frictionally engaging the broad surfaces of the shank whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

2. In a winker including a casing, a male contact prong having a shank and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely affixing the thermoblade to the shank in exact angular relationship and position with respect thereto, bosses in one piece with the casing and extending from said walls into the groove, a boss on one of said walls being intermediate a pair of bosses on the opposite wall, said shank being located in said groove and being flexed by said bosses so as to provide a tight frictional engagement between said bosses and shank whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

3. In a winker including a casing, a male contact prong having a. shank and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely aflixing the thermoblade to the shank in exact angular relationship and position with respect thereto, bosses in one piece with said casing and extending from said walls into the groove, one of said walls having two bosses and the opposite wall having a single boss, the perpendicular distance from the tip of said one boss to an imaginary line drawn between the tips of the two bosses being less than the thickness of the shank, said shank being located in i said groove and extending at least over said bosses so that the shank is flexed by depression at one side where it is engaged by the single boss against the supporting action of the two bosses on the other side whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

4. In a winker including a casing, a male contact prong having a shank and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely aflixing the thermoblade to the shank in exact angular relationship and position with respect thereto, one of said walls includ ing a boss in one piece therewith extending into the groove, the other of said walls including a pair of spaced bosses in one piece therewith extending into the groove, the perpendicular distance between the tip of the one boss and an imaginary line between the tips of the pair of bosses being less than the thickness of the shank, said shank being located in the groove and being tightly frictionally engaged by said bosses, whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

5. In a winkler including a casing, a male contact prong having a shank and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely affixing the thermoblade to the shank in exact angular relationship and position with respect thereto, said shank being in said groove, one of said walls having a boss extending in one piece therefrom into the groove, the other of said Walls having a pair of spaced bosses extending in one piece therefrom into the groove, the perpendicular dis tance from the tip of said one boss to the imaginary line between the tips of the pair of bosses being less than the thickness of the shank and having been shaved by introduction of the shank into the groove whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

6. In a winker including a casing, a male contact prong having a shank and an internal stationary contact fixed in said casing in spaced relationship to said shank: that improvement comprising the combination of walls within the casing forming a groove, a thermoblade adapted to flex into and out of engagement with said stationary contact, means positively and securely affixing the thermoblade to the shank in exact angular relationship and position with respect thereto, a single boss of round crosssection in one piece with and extending from one of said walls into the groove, a pair of spaced bosses of V-shaped cross-section in one piece with and extending from the other of said walls into the groove, the perpendicular distance from the tip of said one boss to an imaginary line between the tips of the other bosses being less than the thickness of the shank, said shank being located in said groove and being thereby tightly frictionally engaged by said bosses whereby to positively and firmly hold the prong in a set position and thereby locate the thermoblade in an exact predetermined position within the casing with respect to said stationary contact.

References Cited in the file of this patent UNITED STATES PATENTS 1,687,167 Mann Oct. 9, 1928 2,110,035 Chirelstein Mar. 1, 1938 2,406,154 Medlin Aug. 20, 1946 2,501,996 Dillon Mar. 28, 1950 2,508,637 Bolesky May 23, 1950 2,6 7,567 Bell Feb. 3, 1953 

